Refrigerator



June 30,1931. 'L'LUND' 'AARb ,8 0

' REFRIGERATOR Filed A ril 8, 1926 I Patented June 30, 1931 UNITED:STATES PATENT OFFICE IVAR LUNDGAARD, OF WEST HARTFORD, CONNECTICUT,ASSIGNOR, BY MESNE ASSIGN- MENTS, '10 DEVON MANUFACTURING COMPANY; 015BOSTON, MASSACHUSETTS, A. v

CORIBOIPATION OF MASSACHUSETTS REFRIGERATOR Application filed April 8,1926. Serial No. 100,485.

This invention relates to the construction and cooperative relation ofthe casing and the refrigerating means of a refrigerator of the type inwhich'the space for containing the matter'to be maintained at thedesired reduced degree oftemperature and the refrigerating elementcontaining the refrigerant are both' located within a heat insulatedcasing, and the refrigerating function is effected by a gaseousrefrigerating medlum that is hermetically sealed within the caslng andis circulated about the walls of the re ceiving space and therefrigerating element so as to convey heat from the former to thelatter. 7 7

The object of the invention is to produce a refrigerator of thischaracter which mav be built at a relatively low cost and which willfunctionvery efliciently and economically.

In attaining this end the casing' is rovided with one or any number ofcharm ers for receiving the food or other products, substances or matterto be refrigerated, the casing walls being heat insulated and hermet- 5ically sealed from the outer air, and the food receiving chamber orchambers, while accessible fromthe outside, being hermetically sealedfrom the interior of the casing in which they are located. Therefrigerating element, containing within it'the refrigerant that is alsoscale from the refrigerating chamber, .is located in the interior of thehermetically sealed casing or in a chamber having air-tight and heatinsulated walls communicating therewith. The refrigerating medium whichis in the hermetically sealed casing andis employed to absorb heat fromthe walls of the food chamber or chambers and deliver it-to therefrigerating element, is desirably air, while the refrigerating elementmay be any of the commonly used temperature reducing means, such as anexpansion coil, brine tank or ice box, but preferably is a compressingengine in which a1r is compressed to expel-its heat and allowed toexpand to draw heat from the refrigerating medium. Asa result of thisarrangiment the gaseous refrigerating medium, w ch f air is notcorrosive, noxious, inflammable or explosive, is caused to circulate.about the eration.

an a1r expansion chamber as the refrigeratwalls of the refrigeratingelement and walls v. of the food receiving chambers with nocommunication whatever with the external atmosphere; it continuouslyperforms its heat conveying function without change andafter itsmoisture content has been dried out it always remains-in the samehygroscopic con- -dition so that no heat-insulating frost can accumulateupon the refrigerating element and cause a reduction in the efficiencyof op- This refrigerator may be used for refrigerating any desiredmatter, but for the purpose of illustrating the invention it is shown asin the form of a refrigerator that is par- 55 ticularly designed\forkeeping ice cream atthe desired temperature by the employment of air asthe refrigerating medium,- which medium is cooled andcirculated by arefrigerating element the temperature of which is reduced by theexpansion of air in a heat exchange engine, and therefore for thepresent purpose the invention will be described as embodied in an icecream refrigerator employing airas the refrigerating mediuin and ingelement.

In the accompanying drawings Fig, 1 shows a horizontal section of such arefrigerator taken on the plane indicated by the dotted line '11 on'Fig.2. Fi 2 shows a central vertical section of the re rigeratorQ In theparticular embodiment of the inven-- tion illustrated the casing isillustrated as having a sheet metal exterior shell 1 for mechanicalprotection and ornamental purposes, and an insulating wall 2 preferablyof com- ,pacted sheets of cork and binder, for reducing thef-conductionof heat from the outer atmos here into-the refrigerating chamber 3.

In t e form shown there are six cylindrical vsheet metal food chambers 4entered into the a casing and supported on a plate5. that is arranged alittle distance above the bottom of the chamber in the .casin The wallsof these food chambers are a1r-tight and their. upper ends are tightlyjoined to'heat insulat-' ing sleeves fifwhich extend through'the topinsulating wall and are similarly joined to the metal exterior casing.Removable covers 7 are placed in the food chamber openings for thepurpose of keeping them closed. The food or other articles, products, ormatter to be refrigerated may be placed packaged or exposed in the foodchambers when the covers are removed, but in the drawings there areshown cans 8 such as are commonly used for containing ice cream. As aresult of this arrangement the walls of the food containing 10 chambersare hermetically sealed from the refrigerating chamber in the casing andare heat insulated from and hermetically joined to the outer or metallicwall of the casing so that they will rapidly conduct heat from the foodchambers to the refrigerating chamber and will not conduct heat to orpermit the admission of moisture from the outer atmosphere. e I

The heat exchange engine illustrated is of the air compressor type shownin Patent 1,240,862 issued to me Sept. 25, 1917, .and being fullydescribed in said patent the details are not herein illustrated anddescribed. It is sufficient to state that the compressing means aredriven from any suitable source of power by the pulley 9 having fanblades 10, and that the air compressed and expanded therein absorbs heatthrough the cold head 11 and discharges heatthrough the hot head 12j,the internal air-passing from the cold head to the hot head through theinterchanger 13, -and the heat from the hot head 12 being carried awayand dissipated in the outer air by the draft produced by the fan 10, asindicated by the arrows in Fig. 2.

' For the purpose of this description the cold head or other means forabstracting heat is termed the refrigerating element, the air within thecompressor is termed the refrigerant, the air that circulates around thehot head is termed the cooling medium, and the air or other gaseousfluid that is hermetically sealed in and circulates within the casingabout the walls of the food chambers and surface of the refrigeratingelement is termed the refrigerating medium.

The refrigerating element is, inthe construction shown, hermeticallysealed Within an extension of the casing. This extension has anair-tight exterior meta-l shell 14 that is removably but tightlyfastened to the shell 1 and thathas a heat insulating lining 15. Thechamber in this extension'communicates with the refrigerating chamber inthe main casing .55 by passage 16. The chamber in the extension isdivided into upper and lower sections by a diaphragm '17 which fitsabout the refrigcrating element in such manner that there is nocommunication between the upper and lower s aces except between the fins18 that exten from the refrigerating element. This diaphragm extendsinto the passage 16, which is further divided into upper and lowersections by a damper 19. By this means the re- 05. frigerating mediumthat circulates in the re frigerating chamber flows through the upperpart of the passage and around the top and between the fins of therefrigerating element and back through the lower part of the passage tothe refrigerating chamber, as indicated by the arrows. The damper 19 hasa shaft 20 that extends, to the outside of the casing where it isprovided with a crank handle 21 by means of which the damper may beturned so as to closethe passage when at any time it is desired toremove or open the extension containing the refrigerating element or todefrost that element and keep the refrigerating medium confined in therefrigerating chamber.

Extending from the damper downto the bottom of the casing, 21 shortdistancefrom one end, is a partition 22 so located as to leave a passage23 in communication with the lower section of the passage from thechamber containing the refrigerating element. Extending upward fromthesupporting plate 5 and fastened to the partition 22 is a wall 24:. Thereis an opening 25 through the partition 22 which affords communicationfrom the passage 23 to the passage 27. Adjacent to this opening is a fan26 the shaft of which extends through the casing and is provided with apulley 28 by means of which the fan may be rotated. This fan acceleratesthe 'cir- 95 culation of the refrigerating medium in the refrigeratingchamber about the walls of the food receptacles and about therefrigerating element, as indicated by the arrows.

- As the air which is employed as the refrigerating medium ishermetically sealed within the casing it remains in a uniformly drycondition, but in order to dry it out and remove any moisture it mayreceive through accident or mischance which becomes frosted on therefrigerating element, an electrical heatin element 29 may be lacedadjacent to there rigerating element or liquefying all frost thatcollects on the refrigerating element. Whatever frost is liquefied bythe heating element is collected in a tray 32 from which'it can bedrained by a pipe 30 with a cock 31. After the refrigerating medium hasbecome once dried it being hermetically sealed always remains d so thatno frost will accumulate on the re rigerating element and thus produce aheat insulator which would materially lower the efiiciency of therefrigerating element, and this is ofv especial advantage where theoperation of the compressor is thermostatically controlled by theEemperature within {the refrigerating cham- The use of air as therefrigerating medium is advantageous as it costs nothing, does not addto the weight of the apparatus, is odor less, is not corrosive, is notnoxious,poison ous, or inflammable, and does not involve handling ormaintenance. 1Air, however, cannot be efliciently used as arefrigerating medium for 130 conveying heat from the walls of a food- Aface of the re chamber to the surface of a refrigerating ele mentwithout precaution being'taken .to prevent the accretion of moisturefrom the surrounding atmosphere. This is particularly true where.temperatures substantially below the freezing point must bejconstantlymaintained, asis the case in cream refri erators.

tmospheric air contains moisture which condenses whenever itstemperatureis-lower than dewpoint and freezes when it drops below freezin point.The refrigerating surgerating element must be held at low temperatures,and if external atmospheric air has access to the refrigerating surfacethe result inevitably is that such surface rogressively becomes coatedwith ice and oses efliciency. With a compressor under .t'herinostaticcontrol there naturally is somewhat of a variation of the pressure orvolume of the conveying; air. Shouldflthe walls'of,

the casing be open to the outer atmosphere this variation would causealternate ingress and expulsion of air, each inspiration depositing itsmoisture contents on the refrigerating element until the accumulationmaterially reduced its refrigerati should rim constantly its effectwould be insufficient. Therefore, in order to obtain andv maintain in 'acheap and satisfactory manner a commercially efficient apparatus theinvention herein described resulted an. essential feature of which isthe em l gaseous (air being considere gas) refrigeroyment of a atingmedium. for conveying heat from the wall of the food receiving-chamberto the surface ofthe refri crating element, this refrigerating mediumeing hermetically sealed in the casing and having, a circulation aboutthe sealed wall of the food chamber and the sealed surface of therefrigerating element .50 that the hygroscopic condition of therefrigeratmg medium always remains the same and frost will not collectupon the refrigeratingelement and reduce its efliciency.

j Furthermore when such gaseous refrigerating medium is dried out andremains dry, as when it is enclosed within a hermetically sealedexterior casing, it is not necemary to provide a metallic protectingshell inside of the heat insulating lining, for ifthe medium contains nomoisture'that insulation is not subject to .the destructive action offrost. Since-there can be no circulation of humid 'air through thejoints in the insulating walls,

these need not be sealed up or otherwise ce- .m'ented beyond the needsof mechanical durability. The economies due to the elimination of thecustomary inner metal lining and the cementing of cork 'oins constitutesan important feature of t 's invention.

The invention claimed is 1 1. A refrigerator comprising ahermeticalcapacity so that even though the heat exc angeengine ly closedcasin containing a refrigerating terior but hermetically closed from therefri era-ting chamber, a heat exchange engine its cold head within saidc and a gaseous refrigerating medium sealfi the refrigerating chamberand designed ,to

circulate in good heat conductive .relation within sis with the wall ofthe food chamber and suri face ofsaid cold head.

3. A refrigerator comprising a hermetically closed main casing cotaimn'g a re ating chamber and a f chamber, said ood chamber beingaccessible from the exterior but hermetically closed from therefrigerating chamber, a refrigerating element located within a heatinsulated air-tight casing 1e.

movably secured 'to said main casing, thechambers in said casings beingin communieating with each oth r, and a gaseous refrig-. f

erating medium seal d within the refrigerating chamber and designedtocirculate inthermal contact with the wall of the food chamberand-surface of the refrigerating element and means selectively operablefor abstracting moisture from the gaseous medium.

4. A'refrigerator comprising a. hermeticala 1v closed casing containinga refrigerating chamber with re -entrant food receiving chambers, 1 saidfood chambers being accesclosed from the refrigerating chamber, a heatsaid casing, and a gaseous refrigeratin medium sealed within therefrigerating c amlos sible .from the exterior but hermetically A Dnoexchange engine with its cold head within ber designed to circulate inthermal contact with thewalls of the re-entrant food chambers andsurface of said cold'head.

5. A refrigerator comprising a hermeticah.

1y closedcasing containing a refrigerating chamber. and a food-receivingchamber, said food chamber being accessible from the exterior buthermetically closed from the refrigerating chamber, a refrigeratingelement \withinsaid casing, a gaseous refrigerating fmedium' sealedwithin the refrigerating chamber and designed to circulate in thermalcontact with the wall of the food chamber and surface of therefrigerating element, a heating element for defrosting therefrigerating element, a tray for collecting moisture erating chamber, arefrigerating element containing a coohng fluld located 1n .aporchamber, the latter being accessible. from the exterior but sealedfrom the refr1g within-the refrigerating chamber, heat conductive meansdisposed about the cold head to transmit heat to. the mediating air,said refrigerating chamber having a normally fixed body of air therein,and a fan for circulating said body of air about the heat conductivemeans.

. IVAR LUNDGAARD.

tion of the refrigerating chamber, said chamber containing a gaseousrefrigerating medium sealed therein, and a fan within the chamber forcirculating th'e'gaseous medium, whereby heat from the food chamber isconveyed to the refrigerating element.

8. A refrigerator comprising a hermetically closed refrigerating chamberand a .food' chamber, the latter being accessible from the exterior butsealed from the refrigerating chamber, a refrigerating elementcontaining a cooling medium located in a portion of the refrigeratingchamber, said chamber containing a gaseous refrigerating medium sealedtherein, and a fan within the chamber for circulating the gaseousmedium, whereby heat from the heat chamber is conveyed to therefrigerating element, and a damper adjoining the cooling element topermit a ready variation in the difference be tween the temperature ofthe same and the food compartment;

9. A refrigerator comprisinga hermetically closed refrigerating chamberand a food chamber, the latter being accessible from the exterior butsealed from the refrigerating chamber, a refrigerating elementcontaining a cooling medium located in a portion of the refrigeratingchamber, said chamber containing a gaseous refrigerating medium sealedtherein, and a fan within the chamber for circulating the gaseousmedium,

said chamber being divided by a partition to direct the gaseous mediumpast one wall portion of the food chamber as it flows away from thecooling element and past another wall portion on its flow back towardthe element.

10. A refrigerator comprising a closed refrigerating chamber and a foodchamber, the latter being accessible from theexterior but sealed fromthe refrigerating chamber,- a heat exchange engine employing air as amediating fluid, said engine having a cold end

